In one such known clamping device (cf. company brochure of the company HILMA-ROMHELD GMBH, D-57260 Hilchenbach (Germany), "Technische Daten/Zubehor, Doppelspannsystem DS 125" [Technical data/accessories double clamping system DS 125], 4.3660, page 1, issue March 1996 and DE 3 925 718 A1) two slides are mounted to move oppositely in the body. A central jaw is mounted in the central region of the body, so that two workpieces can be clamped at the same time. Since the maximum stroke of the slide or slides in such clamping devices is frequently less than 80 mm, the slide has several transverse grooves on its upper side, which are arranged at a centre-to-centre spacing (=pitch) of 40 mm for example. The jaw has a transverse projection matching the transverse groove and is attached to the slide by several fixing screws which engage in the threaded bores of the slide. The jaw can be removed from the slide by releasing the fixing screws and be fitted with its transverse projection in another transverse groove of the slide in order to adapt to different workpiece dimensions. However it is a disadvantage that the unused fixing recesses (transverse grooves) and threaded bores are then exposed. Swarf and cooling lubricant can penetrate into these pockets and can only be removed with difficulty and at cost of a lot of time. The swarf and cooling lubricant can mostly only be removed from the pockets with compressed air; however swarf and coolant are then blown in various directions and can settle again on places which have already been cleaned. There is also the danger of swarf and cooling lubricant being thrown back on to the operator, which can lead to injury to sight.
In order to protect the space of the body adjoining the slide in which the spindle is arranged from swarf, individual sheets, strips carried by the slide, bellows and the like are known. These devices are however not suitable for covering the fixing recesses and threaded bores present in the slide itself. These have previously been closed, if at all, by individual plugs, strips and the like, which however is a real nuisance and time-consuming. Moreover the loose parts can get lost.
Among the constructions cited in the previous paragraph, in which only the space of the body adjoining the slide is protected from swarf, there belongs the clamping device known from U.S. Pat. No. 5,634,253. In this known clamping device the body also has a U-shaped cross-section and two slides sliding in the body. A screw spindle is arranged between the U arms. In order to prevent the penetration of swarf into the space between the U arms of the body a cover plate is arranged on the upper side of the body. In one embodiment (FIGS. 16-18) this cover sheet has a rectangular opening. Grooves are provided in the longitudinal edges of this opening, in which two mutually overlapping cover sheets can slide in the direction of displacement of the slide. Each of these cover sheets is connected to one of the slides, so that it moves with the associated slide and protects the space between the U arms in each slide position from the penetration of swarf. However in this known clamping device there is no plurality of fixing recesses provided in either of the two slides and the jaws also cannot be repositioned relative to the corresponding slide in the slide longitudinal direction, so that the problem referred to above of contamination of fixing recesses does not even occur. Moreover the cover plate and the cover sheets also are only adapted to protect the body from swarf.
The like applies to the vice known from U.S. Pat. No. 2,499,124, in which a cover sheet is guided slidably in longitudinal grooves of the U arms of the body and protects the space between the U arms from penetration of swarf. The cover sheet is here also entrained by the movable slide. The jaw cannot be repositioned relative to the slide.
The latter also applies to the vice known from EP 0 526 432 A1, in which the movable jaw and the slide form a unit. In this vice the screw spindle is mounted in a sleeve, which has a flange. The flange can be brought for coarse adjustment of the sleeve into selective engagement with different recesses which are provided in the U arms of the body of U-shaped cross-section. Filler pieces of nylon can be fitted in the space between the U arms and are intended to prevent the penetration of swarf into the aforesaid space. However the filler pieces cannot prevent the penetration of swarf into the recesses referred to above.
Covers of various constructions, such as telescopic steel covers, roll covers and bellows for example are known from the brochure "Fuhrungsbahnschutz, Spindelschutz, Unfallschutz" [Guideway protection, spindle protection, accident protection] of the company Fipa GmbH Industrie-Ausrustungen, Ismaning, received February 1997, pp. 3 to 7 and 20 and 21.